(a) Field of the Invention
The present invention relates to a combination soap bar composition containing monoglyceridesulfonate and its manufacturing method, more particularly to a combination soap bar composition containing monoglyceride sulfonate having superior moisturizing characteristics and feel during usage as well as a method for economically manufacturing a combination soap bar containing monoglyceride sulfonate.
(b) Description of the Related Art
Toilet soap bars which are made by saponifying fatty acids obtained by decomposing fats and fatty oils using calcium hydroxide, sodium hydroxide, etc. are generally used for washing human bodies. When toilet soap bars are used frequently, their sebum constituents of skin are excessively removed and the softened stratum corneum results in a possible cause of skin irritation since toilet soap bars are strongly alkaline. That is, when alkaline toilet soap bars are repeatedly used over a long time, the skin can become dried and loses its flexibility, easily causing problems of skin roughness. Various additives in toilet soap bar compositions which supply water and oil substances to the skin have been used in order to address the problems of skin drying and skin roughness attributable to the use of these alkaline toilet soap bars. There have also been attempts to alleviate skin drying by adding cosmetic materials, e.g., excess fatty agents, wetting agents, and plant extracts to soaps.
Moisturizing agents used in toilet soap bars, which put moisture on the surface layer of skin and act to block the moisture loss from the skin, play a role to reduce the moisture loss by forming a skin protection layer. Commonly applicable moisturizing agents for skin include glycerin, sorbitol, and natural oils. These form a skin protection layer by creating a membrane on the irregularities of a skin surface that has dried out due to the frequent use of alkaline soaps so that the moisture evaporation is restrained in order to alleviate further skin drying.
However, the current moisturizing agents do not have a function to adsorb external moisture for the skin, but only function in a role of acting as a temporary protective membrane. Furthermore, the current moisturizing agents do not have long lasting effects since they are easily broken away from the skin surface due to physical influences, and also have a problem in that the soap bars in which they are added are easily hydrated and softened when they are increasingly used by a bather in efforts to sustain their effects. That is, the current moisturizing agents do not influence the physiological functions of the skin due to their temporary effectiveness and in most cases actually unfavorably influence soap properties.
There has been increased interest in the manufacturing processes of soaps in which the surfactants are less irritating to the skin and have superior moisturizing effects than those contained in the general fatty acid based soaps in order to address these problems.
For example, a method for improving the moisturizing and feel during usage of liquid type body cleansers by mixing and using anionic, nonionic, and amphoteric surfactants is disclosed in U.S. Pat. No. 5,683,683. Although characteristics which each surfactant retain show synergy effect to constrain skin drying, and hence resulting in the moisturization of the skin when amphoteric surfactants are mixed and used with combination soap bars, an excessive amount of non inoic and amphoteric surfactants in these mixed surfactants has produced problems after long term storage with soap bar discoloration and reduce degrees of bubbling.
Furthermore, U.S. Pat. No. 4,695,395 discloses that the skin protection function is provided by having acyl isethionate, an anionic surfactant, in a combination bar. Although acyl isethionate is a low skin irritant and has superior usage due to its low liquidity and high hydrophilicity compared to general fatty acid based soaps, it has disadvantages in that its high solubility causes water to be easily absorbed into soap resulting in the deterioration of soap physical properties.
Furthermore, Korean Patent Publication No. 95-12209 mentions a method for manufacturing a combination soap bar containing active constituents in which acyl isethionate, a low skin irritant anionic surfactant, is contained as a supporting cleansing constituent. However, this method has not been very economical due to the complexity of its manufacturing method which comprises processes of manufacturing in advance acyl isethionate into certain specified dimensions using fatty acids and sodium isethionate, then processing the acyl isethionate into a slurry phase at a high temperature using liquid and solid phases, ionic water, etc., with the mixing of the slurry phase with a liquid phase soap.
It is an object of the present invention to provide a combination soap bar composition which has an improved soap softness, superior moisturizing effect and usage, and is a low skin irritant.
It is an other object of the present invention to provide a method for manufacturing a combination soap bar containing monoglyceride sulfonate in which the function of combination soap bar is maintained with a simple and economical manufacturing process, wherein a combination soap bar containing monoglyceride sulfonate having superior cleansing power and moisturizing characteristics and feel during usage is produced.
The present invention provides a fatty acid based toilet bar and a combination toilet soap bar composition containing 2 to 35 weight % of monoglyceride sulfonate of the following General Formula 1 in order to achieve the above objects: 
where R is an alkyl having 7 to 21 carbon atoms, and M is sodium, potassium, triethanolamine, or ammonium.
Furthermore, the present invention provides a method for manufacturing a combination soap bar containing monoglyceride sulfonate characterized in that the manufacturing processes consist of (a) manufacturing a fatty acid based liquid phase soap by adding electrolyte and neutralizer to fatty acids; (b) manufacturing mixed liquid phase soaps by adding chlorohydroxy sulfonate to the above liquid phase soaps and agitating; and (c) manufacturing soaps with the above associated soap manufacturing equipment by drying the above mixed liquid phase soaps.
In the following detailed description, only the preferred embodiments of the invention have been shown and described, simply by way of illustration of the best mode contemplated by the inventor(s) of carrying out the invention. As will be realized, the invention is capable of modification in various obvious respects, all without departing from the invention. Accordingly, the description is to be regarded as illustrative in nature, and not restrictive.
The present invention is described in detail below.
The combination soap bar composition of the present invention contains general fatty acid based soaps as a main cleansing agent and 2 to 35 weight %, preferably 5 to 20 weight %, of monoglyceride sulfonate of the General Formula 1 below as a supporting cleansing agent.
Typical examples of monoglyceride sulfonate used in the present invention having the below General Formula 1 include sodium cocomoglyceride sulfonate, sodium tallow, monoglyceride sulfonate, sodium palm oil, monoglyceride sulfonate, sodium palm kernel monoglyceride sulfonate, etc. and a mixture made by mixing one or more of the above can be used: 
where R is an alkyl having 7 to 21 carbon atoms, and M is sodium, potassium, triethanolamine, or ammonium. RCOO having the above R is obtained from single or combined fatty acids which are derived from fats of tallow or lard, plant oil such as coconut oil, palm oil, or palm kernel oil.
Although monoglyceride sulfonate which manufactured by the following method is used in the present invention, its manufacture is not restricted to the following method.
Monoglyceride sulfonate can be manufactured after sodium chlorohydroxy sulfonate, an intermediate, is produced using epichlohydrin, reductant sodium sulfite, etc. The monoglyceride sulfonate used in the present invention is manufactured by transesterification using alkali salts of higher fatty acids. The above higher fatty acids can use a single or combined fatty acids which are derived from fats of tallow or lard, plant oil such as coconut oil, palm oil, or palm kernel oil.
The manufactured monoglyceride sulfonates show the following characteristics:
(i) low human skin irritation since it contains ester groups in its molecules;
(ii) even though it has a lower melting point than general fatty acid soaps, it has superior physical properties with water since it has a higher melting point and a lower solubility than other surfactants due to the affect of hydrogen bonds between the negative electric charges of hydroxy groups and sulfonates; and
(iii) superior skin moisturization and feel during usage are provided due to the bond strength with water molecules enhanced by the hydroxy group of hydrophilic parts during the initial or repeated uses of soaps.
The soap softness is improved by the above characteristics and a combination soap bar composition having superior moisturization and feel during usage can be manufactured when 2 to 35 weight %, preferably 5 to 20 weight % of monoglyceride sulfonate, is used as a supporting cleansing agent in a combination soap bar composition of the present invention. When two or less weight % of the above combination soap bar composition is used, moisturization and xe2x80x98feel during usagexe2x80x99 characteristics deteriorate, even though the soap softness remains good. When 35 or more weight % of the above combination soap bar composition is used, softness of the toilet soap bar deteriorates, although moisturization and feel during usage remain superior
Furthermore, general fatty acid based toilet soap bars can be used in the present invention that are made by neutralizing single or combined fatty acids obtained from animal oil and fat of beef tallow, lard, etc., plant oils such as coconut oil, palm kernel oil, palm oil, palm stearin oil, etc. with sodium hydroxide, potassium hydroxide, and triethanolamine. Typical examples of general fatty acid based toilet soap bars include sodium tallowyl soap, cocoyl soap, or a mixture of one or more thereof.
1 to 25 weight % of two to three or more surfactants salts normally used in a combination toilet soap bar, i.e., alkyl sulfates such as acyl isethionate, sodium laureth sulfate, sodium lauryl sulfate, etc., alkyl sulfosuccinate, alkyl glyceryl ether sulfonate, acyl sarcocinate, acyl taurate, alkyl sulfoacetate, and alkyl ether sulfate can be used considering the inherent characteristics of each surfactants in the range in which the effects of the present invention are not deteriorated in a combination soap bar composition of the present invention.
In order to manufacture the solid phase soaps with a combination soap bar composition of the present invention, a combination soap bar composition of the present invention can use a mixture of one or more compounds selected from the group consisting of binder, plasticizer, and vehicle. Binder and plasticizer improve the soap manufacturing workability by providing soaps with bond strength and plasticity. They also influence the soap hardness after manufacturing and physical properties such as softness, degree of bubbling, smoothness, etc. while in use. Higher fatty acids such as those generally used higher fatty alcohols, coconut fatty acids, etc., hardened oil and fat, paraffin wax, polyester, polyethylene glycol, sodium stearate, hardened cator oil, fatty alkyl ketone, etc. can also be used. Furthermore, ordinarily used dextrin, starch, salt, talc, etc. can be used as vehicle, which plays a role of maintaining the interior structural stability of the final products or the product harness
Furthermore, 5 to 20 weight % of moisture, and other constituents used in a normal toilet soap bar, that is pigments like white pigment such as titanium dioxide, etc., perfumes, antioxidant, metallic ion sealing agents such as ethylenediaminetetraacetic acid, etc., and other additives can be used in a combination soap bar composition according to the present invention. The other constituents, however, except for moisture, are used in very small amounts.
A combination soap bar explained in the present invention can be manufactured by various methods. Manufacturing methods of ordinary combination soap bars include a manufacturing method consisting of the steps of adding cleansing agent and additives to a mixer and then mixing in a mixture for a certain period, remixing the mixture uniformly in the milling process, and consequently manufacturing soap in a general soap process. Additionally there is another manufacturing method consisting of the steps of manufacturing part or all of the additives except for the main cleansing agent in a slurry, mixing the slurry with main cleansing agent, and consequently manufacturing soap in a general soap process.
Although a method for manufacturing a combination soap bar composition for an embodiment of the present invention comprises the steps of adding monoglyceride sulfonate and other additives to a mixture of fatty acid based toilet soap bar, mixing for five minutes, and then uniformly mixing the mixture in a three stage roll mill, and then mixing, molding, extruding and forming a shape according to an ordinary soap manufacturing process, the combination soap bar manufacturing method of the present invention is not restricted to this.
Furthermore, the present inventors found that a combination soap bar composition having superior general physical properties and moisturization could be manufactured by manufacturing a low irritant anionic surfactant and monoglyceride sulfonate as a supporting cleansing agent of general fatty acid based soaps, roll milling or making monoglyceride sulfonate into a slurry phase and containing it in a soap. However, the above soap manufacturing method is not economical since after a supporting cleansing constituent of monoglyceride sulfonate is manufactured, soap is manufactured by reprocessing it with a milling or a slurry process of a general fatty acid based soap.
Therefore, as a result of continuous studies on how to manufacture a combination soap bar containing a supported cleansing agent, i.e., monoglyceride sulfonate, in an economical way, the present inventors generated a manufacturing method of a combination soap bar containing monoglyceride sulfonate of the present invention by discovering that when chlorohydroxy sulfonate (hereinafter referred to as xe2x80x9cchlorosulfonatexe2x80x9d) is added to a liquid phase soap in a soap manufacturing process and certain reaction conditions are provided, a combination soap bar containing monoglyceride sulfonate can be manufactured, and the quality of the physical properties and mosturization of the soap can be maintained at the same or at a higher level during water absorption, when compared to a soap manufactured in a milling or a slurry phase after synthesizing monoglyceride sulfonate.
The present invention is a method for manufacturing a combination soap bar containing monoglyceride sulfonate characterized in that the soap manufacturing processes in soap manufacturing equipment consist of (a) manufacturing fatty acid based liquid phase soap by adding electrolyte and neutralizer to fatty acids; (b) manufacturing a mixed liquid phase soap by adding chlorohydroxy sulfonate to the above liquid phase soap and agitating; and (c) drying the above mixed liquid phase soap.
The above fatty acid based liquid phase soap of the present invention is manufactured by adding electrolyte and neutralizer to fatty acids, and the moisture content is preferably 20 to 35 weight %. The above fatty acids are single or combined fatty acids obtained from animal oil and fat such as beef tallow, lard, etc., plant oil such as coconut oil, palm kernel oil, palm oil fat, palm stearin oil, etc.
Alkali metal, more preferably sodium chloride, is used as the above electrolyte. The above sodium chloride is preferably 0.01 to 1 weight %, more preferably 0.1 to 0.5 weight % of fatty acid based liquid phase soap. Furthermore, the above neutralizer is 25 to 50% (w/w) of sodium hydroxide or potassium hydroxide solution.
Furthermore, fatty acids, electrolytes and neutralizers to be used in the above liquid phase soap manufacturing are reacted in a temperature range of 50 to 90 degrees centigrade, preferably 60 to 80 degrees centigrade, and a liquid phase soap formed by the above reaction should be maintained in a temperature range of 75 to 100 degrees centigrade, preferably 85 to 95 degrees centigrade. A liquid phase soap temperature should be maintained by adjusting an increasing temperature of these additives since temperature generally increases due to an exothermic reaction when neutralizers are added to fatty acids.
Furthermore, the above chlorosulfonates are preferably 1 to 12 weight %, more preferably 2 to 7 weight %, of a combination liquid phase bar manufactured by mixing the above fatty acid based liquid phase soap with chlorosulfonates. The monoglyceride amount is also less in a manufactured combination soap bar when the above chlorosulfonate amount is less than 1 weight %. The viscosity or phase of a combination liquid phase soap is also changed so that the smooth manufacturing of soaps in the ordinary fatty acid based soap manufacturing equipment can be difficult when chlorosulfonates exceed 12 weight %.
One example of the methods for manufacturing the above chlorosulfonates to be used in the present invention is as follows. After a reductant, sodium sulfite, sodium bisulfite, or sodium methabisulfite, is mixed and dissolved with water, epichlohydrine is added and chloro sulfates are manufactured by reaction. The structural formula of chlorosulfonate manufactured by the above method is as in General Formula 2: 
where M is sodium, potassium, ammonium or triethanol ammonium.
There is also a method (hereinafter referred to as xe2x80x9ccontinuous type processxe2x80x9d) for mixing with a liquid phase soap by manufacturing chlorosulfonate solution and another method (hereinafter referred to as xe2x80x9cbatch type processxe2x80x9d) for putting a powder phase chlorosulfonate into a liquid phase soap among the methods for adding chlorosulfonates in the present invention. The continuous type process is preferable.
The chlorosulfonate solution to be used in the above continuous type process is manufactured by dissolving chlorosulfonate with water, with the above solution containing 20 or more weight %, preferably 30 to 45 weight %, of chlorosulfonates and manufactured at a temperature of 20 or more degrees centigrade, preferably 40 to 70 degrees centigrade. Although a chlorosulfonate solution without water can be used by mixing polyhydric alcohols (such as propylene glycol, glycerin, sorbitol, polyoxyethylene glycol), oils (such as mineral oil), and neutralizers (such as caustic soda, caustic potash, and triethanolamine), it is preferably manufactured such that chlorosulfonates are not in a supersaturation condition, if possible.
A batch type manufacturing method, a method wherein monoglycerides are contained in a combination soap bar by putting a certain amount of powder type chlorosulfonate into a liquid phase soap of which the weight and volume are known, is the same manufacturing process as a continuous type process except that chlorosulfonates are added in a powder phase and not in a solution phase. A powder phase chlorosulfonate used in a batch type process is composed of 90 or more weight %, preferably 95 or more weight %, of active constituents.
The temperature of liquid phase soaps and chlorosulfonate solution is properly maintained and increased such that the temperature of a combination liquid phase soap is maintained from 75 to 100 degrees centigrade, preferably 85 to 95 degrees centigrade, in the manufacturing process of a combination soap bar composition of the present invention.
Even if particular mentions are not made herein, a batch type process is to be regard as having equal status with a continuous type process in the manufacturing process of a combination soap bar composition of the present invention. Proper managing of temperature, agitating speed, and time of the combination the liquid phase soap with manufacturing methods and conditions of fatty acid based liquid phase soap and chlorosulfonate solution is necessary in order to maximize the yield of monoglyceride sulfonates by adding chlorosulfonates to a liquid phase soap. Monoglyceride sulfonate formed during the above agitating procedure can be represented in the following General Formula 1: 
where R is an alkyl having 7 to 21 carbon atoms, and M is sodium, potassium, ammonium, or triethanolammonium.
Although the above agitating speed depends on the volume of the reactor in which a combination liquid phase soap is contained, there is not much difference in the contained formation amount in the present invention so long as there is an agitating speed such that a combination liquid phase soap has the sufficient contact area. If possible, a high speed agitation is preferable.
Furthermore, a constant agitating time, temperature, and agitating speed are necessary in order to form monoglyceride sulfonates in a combination liquid phase soap. A combination liquid phase soap is agitated for more than 20 minutes, preferably 30 minutes to 4 hours, since added chlorosulfonates can exist in a non-reacted condition not participating in the reaction, and the formed monoglyceride sulfonates are hydrolyzed to influence on the yield.
Although a part of chlorosulfonate used in the present invention and formed monoglyceride sulfonate is hydrolyzed in an alkali and at a high temperature to form a part of dihydroxypropane sulfonate and sodium chloride as a side reactant, it is not at a level so as to influence quality. A solid phase soap falling within manufacturing and commercial parameters when chlorosulfonates are used is within the range of the present invention.
Furthermore, additives which can normally be used in a toilet soap bar, i.e., perfumes, pigment, antioxidant, metallic ion sealing agent, etc., can be added during the manufacturing process of a combination soap bar or after the manufacturing of a cleansing agent in a combination soap bar composition of the present invention.
When soap is manufactured in soap manufacturing equipment by drying a combination liquid phase soap of the present invention, a combination soap bar containing monoglyceride sulfonates is produced. All generally usable drying methods and soap manufacturing equipment can be used in the above drying method and soap manufacturing process.
Examples and comparative examples of the present invention are described below. However, the following examples are only for illustrating the present invention and the present invention is not restricted to the following examples.